1. Field of the Invention
The present invention relates generally to improvements in disposable electrode devices and more particularly pertains to a new and improved template for placing a plurality of electrodes on a patient""s chest.
2. Description of Prior Art
An electrocardiogram (ECG) is a painless recording of the heart""s electrical activity. This electrical activity is detected by small metal electrodes which are placed on the patient""s chest and sometimes on the wrists and ankles. The electrical signals detected are carried from the electrodes through wires to an ECG machine. The ECG machine transforms the signals into standard patterns or waves. The different waves represent the different areas of a human heart through which tiny electrical currents flow, causing the heart to contract and relax. The P wave, for example, represents the current in the atria, or the upper chambers of the heart. The QRS complex represents the current in the ventricles. The T wave represents the heart""s rest period as it repolarizes, or recharges electrically between heart beats.
The paper tracing of the ECG waves produced by the ECG machine shows not only the heart rate and heart rhythum, it can also give important clues about damage to the heart muscle or pericardium, the membrane around the heart. Furthermore, changes in ECG waves from one session to another may reflect the action of certain cardiac medications. ECG abnormalities may also indicate that a serious chemical imbalance exists in the blood which is affecting the heart""s electrical activity. An ECG can distinguish between a heart attack that occurred in the past and one in progress at the time the ECG is being taken.
Besides obtaining the recording of the heart""s electrical activity during rest, the more important ECG readings are taken while during exercise or while going about normal ambulatory activity. The exercise ECG records heart patterns while a person walks on a treadmill or pedals a stationary bicycle, for example. This technique is also called a stress test. This type of ECG is more likely to spot abnormal heart patterns, and an insufficient blood or oxygen supply to the heart muscle during exercise. Ambulatory ECG or Holter monitoring (ECH) records heart patterns usually over a 24-hour or longer period of time while a person goes about his daily activities. The standard Holter monitoring process requires that small electrodes that stick to the skin are connected to a portable recording device on a shoulder strap or belt worn under the patient""s clothing. The recorded information can then later be analyzed by a computer and printed out much like a standard ECG. These ambulatory monitoring systems also can be used to transmit heart patterns to a hospital or doctor while a person is having symptoms. When a symptom develops while wearing the ECH, the patient simply dials a telephone number and transmits the readings from the Holter recorder over a telephone line.
The ECH systems are used generally to detect or monitor abnormal heart rhythms, or arrhythmias, which arise from problems with the electrical conduction system of the heart. Arrhythmias can occur anywhere in the atria or the ventricles of the heart. These arrhythmias can be either too slow or too fast. Abnormally slow rhythms sometimes results from slower firing of impulses, a condition called sinus bradycardia. An abnormally slow heart beat is dangerous. The heart does not pump enough blood to supply the brain and the rest of the body with oxygen. In such cases, episodes of dizziness, light headedness or fainting may occur.
Abnormally fast heart rhythms, such as for example, atrial fibrillation in which the atria contracts in a rapid uncoordinated manner, reduces the pumping efficiency of the heart. In a person with heart disease, the reduced pumping efficiency may lead to heart failure or stroke. Another more dangerous type of rapid arrhythmia is ventricular fibrillation in which ventricular contractions are rapid and chaotic. This fibrillation prevents the ventricles from pumping blood efficiently and can lead to death within minutes. Ventricular fibrillation is usually reversed with an electrical defibrillator, a device that delivers a shock to the heart. The shock briefly stops the heart from beating and when the heart beat starts again, the SA node is usually able to resume a normal beat.
The current standard method of obtaining ECG data requires the placement of up to ten single electrodes upon a patient""s chest in order to monitor the heart rhythm and obtain the ECG tracings. The manual placement of these electrodes is tedious with technical error resulting in increased variance from monitor session to monitor session with decreased reproducible results. Moreover, these individual ECG electrodes are produced by a variety of manufacturers in different ways using different materials and styles and having different sensitivities.
There have been attempts in the prior art to provide a flexible sheet which carries a plurality of fixed electrodes positioned in a specific configuration which allows the placement of these plurality of electrodes on a patient""s chest in a manner which provides consistency in the dimensional relationship between the electrodes on the flexible sheet. However, these prior art methods do not have any way of ensuring that the flexible sheet, with its plurality of electrodes, is placed in the correct position on the patient""s chest every time.
The present invention permits quick, easy and correct placement of a ten electrode array carried by a flexible template to monitor the electrical activity of a patient""s heart, by a locating tab on the template. A pair of defibrillation electrodes may also be located on the template ready for use, if necessary. The template and electrodes are x-ray invisible so that the template and electrodes need not be removed during diagnostic procedures. The template is adapted to connect to the three or four most popular monitoring and defibrillation machines used by paramedics and in hospital emergency rooms, critical care units, telemetry wards, outpatient Holter and Event monitors. The template also allows quick and accurate placement by the lay person in any setting. The template proves its critical worthiness when applied by the lay person during an out of hospital cardiac event when used in conjunction with an AED.